Correlation between results of head-up tilt test and clinical features in patients with syncope or presyncope

Head-up tilt test (HUTT) is a well-established diagnostic tool in patients with suspected vasovagal syncope. Identification of factors that predict a positive HUTT result could simplify diagnostic steps. The aim of this study was to assess the correlation between clinical characteristics of patients with suspected neurocardiogenic syncope or presyncope and results of HUTT.

The study group consisted of 90 patients (55 men, 35 women; mean age, 43.2 +/- 17 years) with a history of syncope or presyncope. Cardiological and neurologic test findings were normal in every patient. The patients were tilted to a 70 degrees position for 45 minutes. If the first phase produced a negative response, the patients received 400 mug of sublingual nitroglycerin for the second phase and continued to be tilted for an additional 15 minutes.

Sixty-four patients had a positive HUTT result, characterized by a vasodepressive response in 26 patients, mixed response in 24 patients, and cardioinhibitory response in 14 patients. In logistic regression analysis, the presence of prodromal symptoms was a predictor of a positive HUTT result (P = .002).

We showed that the prognostic performance of clinical features, including the time interval between the last episode and HUTT, the number of syncope or presyncope episodes, age, and sex, was not ideal. The presence of prodromal symptoms might be more likely to predict a positive response during HUTT.